﻿using System;
using System.Collections.Generic;
using System.Configuration;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApp1
{
    //默认访问修饰符internal,无法实例化可继承
    abstract class  Student
    {
        public int age;

        public char sex;
        public int height { get; set; }

        public void Skill ()
        { 

        }

        Grade Grade = new Grade();
    }

    //可以被实例化
     sealed class Grade : Student 
     {

     }

    //public程序中都可以使用这个类static中也只能有static成员

    public static class School 
    {
        public static int grade;
        public int teacher;
    }


}
